Means for preventing moisture from entering transformer-tanks.



F. W. HADLEY. MEANS FOR PREVENTING MOISTURE FROM ENTERING TRANSFORMER TANKS.

APPLICATION FILED MAILZZ, 1911.

Patented Jan. 2, 1912.

FREDERICK W. HADLEY, OF ATLANTA, GEORGIA.

MEANS FOR PREVENTING MOISTURE FROM ENTERING TRANSFORMER-TANKS.

Specification of Letters Patent.

Patented Jan. 2,1912.

Application filed March 22, 1911. Serial No. 616,279.

To all whom it may concern:

Be it known that I, FREDERICK WV. HAD- LEY, a citizen of the United States, residing at. Atlanta, in the county of Fulton and State of Georgia, have invented certain new and useful Improvements in Means for Preventing Moisture from Entering Transformer-Tanks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will onable others skilled in the art to which it appertains to make and use the same.

This invention relates to a process of and an apparatus for maintaining the insulation in a transformer employing oil between its coils in a high state of efficiency, and has for its object to utilize the natural action of such transformers in expelling air therefrom and .in sucking air back therein to aid in maintaining said efficiency.

To these ends the invention consists in the novel steps constituting my process, and in the novel combinations of parts more fully hereinafter disclosed and particularly pointed out. in the claims.

Referring to the accompanying figure of drawings forming a part of this specification, and which is a diagrammatic view illustrating one means of carrying out my invention :1 indicates any suitable transformer tank containing any suitable insulating oil 2, and having the ordinary system of wiring 3 and 4:-

15 indicates any suitable transformer coils and above the oil 2 in such tanks there occurs a space 5 containing a greater or less volume of air and vapor, and as ordinarily constructechwhen the transformer is working, the oil is naturally heated up and this air is greatly expanded. The oil also expands, and thus creates an additional pressure upon the contained air. In order to accommodate this change in volume and pressure, the transformer is sometimes pro vided with a vent which prevents the air from passing out through leaks. Upon cutting off the current, of course, the oil cools down, and the air left in the transformer is naturally of a reduced volume, and consequently additional air is sucked in through said vent or through leaks. It thus follows owing to this natural action of so called,

breathing in transformers, during which air is constantly exhaled and inhaled, that no matter how free from moisture the insulating oil may have originally been, yet

after the transformer has been operating for a given time more or less moisture Wlll be introduced into the transformer by the constantly incoming fresh air, and its insulation will accordingly be impaired. Especially will this be the case when the transformer is located in a damp atmosphere such as is usually found around or near water falls, and on rainy days or during damp weather.

My invention entirely obviates the troubles and disadvantages arising from the introduction of moisture into the transformer tank in the manner above disclosed, as will be now set forth.

I provide a pipe 6 which may communicate with the interior of the transformer at any desired point, and which leads to any suitable drier 7 which may be of the calcium chlorid type having the perforated supports 8 and drying charges 9, as shown. The said drier is provided with a suitable outlet 10,

and preferably valves 11 and 12 control the inlet and outlet respectively. It now follows that when the volume and pressure of the air in the space 5 increases from the causes above disclosed, the excess of air will flow through the pipe 6, the tank 7 and out of the exit 10 into the atmosphere. On the other hand, when the volume of air in the space 5 decreases, air from the atmosphere no matter how much moisture it may contain will flow through the exit 10 into the tank 7 and passing through the drying charges 9 will be robbed of its moisture, whereupon dry air will then flow through the pipe 6 back into the space 5 to supply the deficiency there existing. In other words, the transformer will breathe 0r inhale and exhale dry air automatically, so that no additional moisture will be introduced into the oil 2 at all. It, therefore, follows that if the oil when at first placed in the transformer, is thoroughly dry or dehydrated, it will not need further attention on that score provided the transformer is equipped with my apparatus.

I am'familiar with the fact that it is common to dehydrate the oil by means of chemicals before it is placed in the transformer, and I am also familiar with the fact that it is common to pump out the space 5 when the transformer is first filled in order to get out ofthe tank all of the moisture which may have existed therein before the oil was introduced, but it will be seen my invention radically difiers from all of the above classes of inventions, in that said other inventions make no provision whatever for keeping the oil dry after it has gone into use. My invention, on the other hand, provides a method and means for maintaining the high insulating qualities of the oil throughout the life of the transformer. 4

In addition to the above, oil contained in very large storage tanks often absorbs moisture from the air sucked into said tanks when the oil is removed, but by applying my invention to such tanks this objection is entirely overcome. Further, in the case of transformers, I have found even after the oil has absorbed moisture from any cause, if the space 5 above the oil is kept dry by my apparatus the oil will gradually give up its moisture, and its insulating qualities correspondingly improved.

It is obvious that those skilled in the art may vary the details of the invention without departing from the spirit thereof, and therefore I do not wish to be limited to the above disclosure, except as may be required by the claims.

' What I claim is 1. In a transformer the combination of a tank containing oil and having an air space above said oil; a pipe communicating with said air space; and a drying chamber connected to sai pipe, whereby any air that may be sucked into saidtank must be first subjected to the action of said drying chamber, substantially as described.

2. In a transformer, the combination of a tank containing the transformer coils and oil for insulating the same and having an air space above said oil; a drying chamber provided with an inlet and an exit; and a pipe connected to said inlet and air space, whereby heat from said coils may force said air only through said exit, and upon a lowering of the temperature additional air may besucked only through said chamber back into said space, substantially as described.

In testimony whereof, I affix my signature, in presence of two witnesses.

FREDERICK W. HADLEY.

Witnesses F. F. NoYEs, H. D. BRUMLEY. 

